Comprobando qué conexiones persistentes tengo actualmente en mi ordenador, me fijo en que el Steam se conecta a IPs estáticas de Jazztel:
steam 4251 user 32u IPv4 209594 0t0 TCP localhost:57343 (LISTEN)
steam 4251 user 39u IPv4 214172 0t0 TCP *:27036 (LISTEN)
steam 4251 user 44u IPv4 212455 0t0 UDP *:27036
steam 4251 user 63u IPv4 214173 0t0 UDP *:57278
steam 4251 user 69u IPv4 214592 0t0 TCP 10.80.0.50:54261->137.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 70u IPv4 212638 0t0 TCP 10.80.0.50:34214->128.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 71u IPv4 212563 0t0 TCP 10.80.0.50:36455->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 72u IPv4 212552 0t0 TCP 10.80.0.50:40918->128.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 73u IPv4 212623 0t0 TCP 10.80.0.50:52624->128.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 74u IPv4 212598 0t0 TCP 10.80.0.50:47625->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 76u IPv4 212636 0t0 TCP 10.80.0.50:43927->137.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 77u IPv4 212701 0t0 TCP 10.80.0.50:58811->128.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 78u IPv4 213694 0t0 TCP 10.80.0.50:39197->170.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 79u IPv4 213702 0t0 TCP 10.80.0.50:57694->170.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 80u IPv4 212667 0t0 TCP 10.80.0.50:35662->137.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 81u IPv4 215436 0t0 TCP 10.80.0.50:34014->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 82u IPv4 212707 0t0 TCP 10.80.0.50:60465->128.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 83u IPv4 212725 0t0 TCP 10.80.0.50:58151->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 86u IPv4 216592 0t0 TCP 10.80.0.50:53432->137.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 87u IPv4 216593 0t0 TCP 10.80.0.50:36459->170.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 95u IPv4 224308 0t0 TCP 10.80.0.50:51014->137.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 96u IPv4 224309 0t0 TCP 10.80.0.50:58379->137.219.106.212.static.jazztel.es:http (ESTABLISHED)
steam 4251 user 98u IPv4 213928 0t0 TCP 10.80.0.50:40421->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 75u IPv4 232432 0t0 TCP 10.80.0.50:54436->2.21.48.230:http (ESTABLISHED)
steamwebh 4291 user 99u IPv4 232511 0t0 TCP 10.80.0.50:53889->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 101u IPv4 226758 0t0 TCP 10.80.0.50:53894->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 105u IPv4 232512 0t0 TCP 10.80.0.50:53890->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 106u IPv4 226746 0t0 TCP 10.80.0.50:53891->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 107u IPv4 226751 0t0 TCP 10.80.0.50:53892->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 108u IPv4 226754 0t0 TCP 10.80.0.50:53893->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 109u IPv4 226762 0t0 TCP 10.80.0.50:53895->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 110u IPv4 226768 0t0 TCP 10.80.0.50:53896->178.219.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 111u IPv4 230707 0t0 TCP 10.80.0.50:49211->162.221.106.212.static.jazztel.es:http (ESTABLISHED)
steamwebh 4291 user 114u IPv4 227559 0t0 TCP 10.80.0.50:49212->162.221.106.212.static.jazztel.es:http (ESTABLISHED)
¿Steam utiliza servidores de Jazztel como CDN? Pregunta estúpida ante lo expuesto arriba, pero quizá sólo sea para la web y no para la descarga de videojuegos u otros servicios de Steam.
